July 17, 2013

Neural dust diagram (credit: Dongjin Seo et al.)

In a potential neuroscience breakthrough, University of California Berkeley scientists have proposed a system that allows for thousands of ultra-tiny “neural dust” chips to be inserted into the brain to monitor neural signals at high resolution and communicate data highly efficiently via ultrasound.

The neural dust design promises to overcome a serious limitation of current invasive brain-machine interfaces (BMI): the lack of an implantable neural interface system that remains viable for
a lifetime. Current BMI systems are also limited to several hundred implantable recording sites, they generate tissue responses around the implanted electrodes that degrade recording performance over time, and are limited to months to a few years.

Neural dust could also provide the large-scale recording of neurons required for the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative, the scientists suggest.

System Concept

Neural dust system diagram showing the placement of ultrasonic transceiver under the skull, the neural dust sensing nodes dispersed throughout the brain, and external transceiver (credit: Dongjin Seo et al.)

The neural dust system has three basic elements:

Thousands of low-power CMOS chips — neural dust — are embedded (via fine-wire arrays that are then removed) into the cortex between neurons. They detect extracellular electrophysiological signals via an electrode and a piezoelectric sensor converts ithe signals into ultrasonic signals.

A subdural (the dura surrounds the brain and keeps in the cerebrospinal fluid) ultrasonic transceiver (transmitter+receiver) receives ultrasonic signals from the neural dust.It also powers the neural dust with ultrasonic energy.

A battery-powered external transceiver communicates via ultrasound with the subdural transceiver and transmits the data to an external computer.

Embedded ~2 mm. in the brain, the powered neural dust chips can be as small as tens of microns (millionths of a meter). Ultrasound is attractive for in-tissue communication given its short wavelength and low attenuation.

The design also uses more efficient “backscattering”: instead of transmitting energy, the chips passively modulate ultrasonic energy from the sub-dural transceiver and reflect it back.

The researchers calculate that the neural dust chips can be as much as 10 million times more efficient that chips using electromagnetics (magnetic or electric signals), which have high attenuation in brain tissue. They would be encapsulated in an inert polymer or insulator ﬁlm.

The arXiv paper mentions a number of challenges that need to be addressed in developing a practical system.

Comments (26)

My roomates sometimes come out and mention my thoughts. I scared and uncomfortable. Please explain how I might present myself to explain this phenoemena. Looking for answers and helpful advice. Thankyou

When brain activity can be monitored in this much detail, it must be possible to make a model of the brain. So immortality is almost there for animals, let’s say in 5 years. Not long after that it can be used for humans, let’s also say in another 5 years. So in 2023 my brain can be made immortal.That’s way sooner than singularity year 2045. Right?

It’s a good question. Some considerations: This technology is limited to 2 mm (the cortex) in animal models, not the whole brain. Whether or not such data would provide a useful model would have to be determined. For humans (in the U.S.), implanting these sensors would normally be heavily restricted by the FDA, and to specific areas of the cortex related to lesions. How useful are electrical recordings without also recording the internal and external events related to those recordings? Is is necessary to also record down to the molecular level within neurons? What about neurohormonal events? Etc. This article goes into this in more depth: http://www.kurzweilai.net/preserving-the-self-for-later-emulation-what-brain-features-do-we-need.

OP’s comment falls under the ‘not even wrong’ category, but I will comment on it anyway. Firstly gaining greater details of the brain is always welcomed and it helps in getting us to a working model but until we are actually able to understand the phenomenon known as consciousness, mere “copying” at a macroscopic level probably won’t work. We need to understand why and how the neuron structure enables consciousness, as otherwise we may only have memory but no awareness. Even after that, there is still quite a gap between a working model and allowing a transfer of this our consciousness or whatever we associate with our “self”.

In regards to “immortality”, that’s unfortunately still a way off and even if we don’t experience the normal human death that we experience now, that’s still a far cry from true immortality. I think it is not unreasonable to expect technology to extend our lifespan to hundreds of years in a carbon-based form or maybe thousands of years beyond that but we still probably can’t escape the death of the Sun or ultimately the heat death of the universe.

As long as life have any physical structure, it’d always be subjected to some form of death as that structure can be destroyed.

The proposed concept is for one-way transmission of neural electrical signals converted to ultrasonic signals that can be further encrypted. There is no apparent mechanism for receiving such external signals and applying them to neurons via these devices. Ultrasound itself does have direct effects on the brain though.

Cool idea but the knee-jerk reaction should be “my body is a temple”. In what universe is invading the body in this manner a good idea? Somewhat related: the following paper speaks to the potential dangers of inserting foreign matter in to the body: http://pubs.acs.org/doi/abs/10.1021/nn402145t (iron oxide nanoparticle exposure seeming to disrupt immune cell function)
As with anything along these lines, prove the approach is absolutely benign _first_, then we’ll talk.

Very exciting research, I hope this will allow us to increase the exponential growth in knowledge of the human brain. As far a wide adoption I have a few thoughts.
1. Personally for me to be willing to go forward with implanted augmentation the device will need to be a two way street. I’m not willing to accept the risks of introducing foreign components into my skull if they are unable to talk to my neurons as well as listen to them.
2. Ultrasonics have been shown to be able to resonate within the human skull and create audible tones. Now I expect that with a handful of these minuscule devices will produce so little ultrasonic energy that its not worth talking about. But with systems that scale I would be interested to see an evaluation of the potential unintended interference when you have 1,000,000 of these little resonators inside your head.
3. The implanting process from the article sounds extremely invasive. To cover the brains surface with these resonators it sounds like this would require removal of at least a portion of the skull. If there is a requirement for an open skull procedure… im not a doctor but I imagine that possibility for complications as well as facility requirements become difficult hurdles to overcome.

1. This technology is intended for research with animals and as a replacement for BMI devices for treatment of conditions like quadriplegia, which have similar risks, not for human augmentation (although that’s an interesting area to explore in the future, and one can imagine future neurohackers wireheading pleasure centers or attempting to communicate two-way data). Why would you want them to talk to your neurons?
2. Yes, there are potential adverse ultrasound-related biological effects, so testing of this would likely be done in early animal research. The effects can be reduced by limiting transmit power, duty cycle, and device density (in addition to backscattering). http://www.wikiecho.org/wiki/Biologic_Effects_of_Ultrasound_and_Safety is a good reference, and this issue is discussed briefly in the arXiv paper.
3. Actually, they would probably be less invasive than current procedures, since the wires are withdrawn after implantation, reducing risk of infection and artifacts. For BMI replacement, the devices would normally be limited to the area of the lesion (or suspected lesion). Yes, animal neuroscience research is inherently invasive, and there may be an experimental need to cover the entire cortex in the future.

The Newport News Police and the Virginia State Police have installed yagi-uda laser antennas. These antennas log every computer key stroke every citizen makes. It also enables them to hack into the wireless router in your electric meter, burglar alarm or television set. This enables them to see you in the privacy of your own home. In addition, they have hand held terahertz scanners that enable them to see through your clothes. One Newport News Officer was caught talking about “fat chicks” at the local college over the police radio per the Daily Press. Surveillance issues are not just with the NSA. It’s with all of law enforcement. They plan to make this ubiquitous surveillance so prevalent before anyone knows it exists. They are implanting innocent citizens with microchips and installing yagi-uda laser antennas to record every key stroke or wirelessly tase you in your own home. Go to digitalbarriers.com or read Safeguards in a World of Ambient Intelligence by Springer. On page nine it says they want to know where you, what you are doing and what you are “thinking” every minute. They are getting funding through the “brain initiative”. You’ll be surprised out just how much they can do now.